This invention relates to joystick interfaces and methods of providing position information of a joystick.
Joysticks have been utilized for many years in computer games and other applications. Some conventional joystick configurations include a plurality of potentiometers which individually set a time delay for a corresponding one-shot multivibrator. Movement of the position of the lever of a joystick changes the resistance of the potentiometer and also varies the time delay of the one-shot multivibrator. The measured time delay of the one-shot multivibrator is converted into a position by associated software executing within a host computer. In typical conventional configurations, two or more orthogonally arranged potentiometers are utilized per joystick to obtain related current axial settings of the joystick lever.
Conventional joysticks utilizing multivibrators have associated drawbacks. For example, the accuracy of the potentiometer output readout may be imprecise or inconsistent due to operational or structural imperfections of the multivibrators themselves. For example, readings may vary with changes in temperature and with inherent variations in individual components during manufacture.
Another significant drawback with utilization of conventional joystick arrangements is the demand imposed upon the operating software and hardware resources of the associated host system. An exemplary joystick is available from Microsoft Corporation having the designation Sidewinder Precision Pro. In typical configurations, the joystick operations consume a large amount of bus cycles for intense software loops which continuously poll the joystick system in order to determine the current axial position of the joystick. Such utilization of a large number of bus cycles consumes resources which would otherwise be available for other operations within the computer system providing enhanced system performance.
More recently, joystick configurations have been introduced which operate in a digital domain. Exemplary digital joystick configurations are described in U.S. Pat. Nos. 5,751,235, 5,742,249, 5,710,575 and 5,786,808, each of which is incorporated herein by reference. Some digital joystick configurations utilize analog-to-digital (A-D) converters which provide digital representations of voltages across potentiometers of the joystick. These configurations utilizing analog-to-digital converters have associated drawbacks which include inflexibility to new semiconductor processes and nonlinearities in joystick positioning, for example.
Therefore, a need exists to provide improved devices and methodologies for monitoring the position of a joystick.